Submersible pumping systems are often deployed into wells to recover petroleum fluids from subterranean reservoirs. Typically, a submersible pumping system includes a number of components, including an electric motor coupled to one or more pump assemblies. Production tubing is connected to the pump assemblies to deliver the wellbore fluids from the subterranean reservoir to a storage facility on the surface.
The wellbore fluids often contain a combination of liquids and gases. Because most downhole pumping equipment is primarily designed to recover liquids, excess amounts of gas in the wellbore fluid can present problems for downhole equipment. For example, the centrifugal forces exerted by downhole turbomachinery tends to separate gas from liquid, thereby increasing the chances of cavitation or vapor lock.
Gas separators have been used to remove gas before the wellbore fluids enter the pump. In operation, wellbore fluid is drawn into the gas separator through an intake. A lift generator provides additional lift to move the wellbore fluid into an agitator. The agitator is typically configured as a rotary paddle that imparts centrifugal force to the wellbore fluid. As the wellbore fluid passes through the agitator, heavier components, such as oil and water, are carried to the outer edge of the agitator blade, while lighter components, such as gas, remain close to the center of the agitator. In this way, modern gas separators take advantage of the relative difference in specific gravities between the various components of the two-phase wellbore fluid to separate gas from liquid. Once separated, the liquid can be directed to the pump assembly and the gas vented from the gas separator.
While two or more prior art gas separators can be connected in tandem to improve the overall removal of gas from the produced fluid, the coupling that connects the shafts will create restriction and disturbance to the fluid flow. The restriction to the fluid flow detrimentally affects the gas separating performance of the system.
There is therefore a continued need for an improved gas separator design that more effectively and efficiently separates liquids from gases in a pumping system. It is to these and other deficiencies in the prior art that the present invention is directed.